Hasil untuk "Physical anthropology. Somatology"

Comité Organizador de las XXXVIII JAPV

Libro de resúmenes de las XXXVIII Jornadas Argentinas de Paleontología de Vertebrados, que tuvieron lugar en la Ciudad de San Luis (San Luis, Argentina) del 21 al 23 de mayo de 2025.

Siyan Zhao, Jiachun Li, Gilles Cuny et al.

A taxonomic study of four tooth genera of euselachian sharks from the Ladinian–Carnian interval of the Guizhou and Yunnan Provinces, South China is presented. They include one euselachian shark of uncertain affinity, two indeterminate neoselachian sharks and one potential hexanchid shark. These four taxa display non-durophagous feeding behaviour, including grasping-swallowing, grasping, tearing and cutting strategies. High-resolution micro-CT scans and 3D reconstructions reveal that Euselachii gen. et sp. indet. and Neoselachii gen. et sp. indet. 1 possess orthodont teeth. Euselachii gen. et sp. indet. exhibits a prominent longitudinal vascular canal, but lacks an ascending pulp cavity, while Neoselachii gen. et sp. indet. 1 features two longitudinal vascular canals and a vascular cavity that ascends into the main cusp. To our knowledge, this study provides the first three-dimensional documentation of dental vascularisation in Triassic chondrichthyans.

Siqi Wang, Mengmeng Zhang, Yude Bu et al.

In scientific and engineering domains, modeling high-dimensional complex systems governed by partial differential equations (PDEs) remains challenging in terms of physical consistency and numerical stability. However, existing approaches, such as physics-informed neural networks (PINNs), typically rely on known physical fields or coefficients and enforce physical constraints via external loss functions, which can lead to training instability and make it difficult to handle high-dimensional or unobservable scenarios. To this end, we propose PhysFormer, a generative modeling framework that is self-consistent at both the data and physical levels. PhysFormer leverages a low-dimensional, physically interpretable latent space to learn key physical quantities directly from data without requiring known high-dimensional physical field parameters, and embeds the physical process of radiative flux generation within the network to ensure the physical consistency of the generated spectra. In high-dimensional, degenerate inversion tasks, PhysFormer constrains generation within physical limits and enhances spectral fidelity and inversion stability under varying signal-to-noise ratios (SNRs). More broadly, this approach shifts the physical processes from external loss functions into the generative mechanism itself, providing a physically consistent generative modeling paradigm for complex systems involving unknown or unobservable physical quantities.

Yiming Zhang, Yingfan Ma, Yanmei Gu et al.

Large Language Models (LLMs) have shown impressive performance in domains such as mathematics and programming, yet their capabilities in physics remain underexplored and poorly understood. Physics poses unique challenges that demand not only precise computation but also deep conceptual understanding and physical modeling skills. Existing benchmarks often fall short due to limited difficulty, multiple-choice formats, and static evaluation settings that fail to capture physical modeling ability. In this paper, we introduce ABench-Physics, a novel benchmark designed to rigorously evaluate LLMs' physical reasoning and generalization capabilities. ABench-Physics consists of two components: Phy_A, a static set of 400 graduate- or Olympiad-level problems; and Phy_B, a dynamic subset of 100 problems equipped with an automatic variation engine to test model robustness across changing conditions. All questions require precise numerical answers, with strict formatting and tolerance constraints. Our evaluation of several state-of-the-art LLMs reveals substantial performance gaps, highlighting persistent limitations in physical reasoning, especially in generalization to dynamic variants. ABench-Physics provides a challenging and diagnostic framework for advancing scientific reasoning in LLMs.

Nicolas Lanchon, Samuel Boury, Pierre-Philippe Cortet

The search for solutions to the theory of weakly non-linear internal gravity wave turbulence is an active research topic. It is notably stimulated by the fact that this regime could drive fine-scale ocean dynamics for which the identification of a physical model could yield improved parametrizations in global oceanic models. In this context, analytical works lead to diverse predictions and the experimental observation of a regime of developed weakly-non-linear internal wave turbulence constitutes a major, still unachieved, objective of experimentalists in the field. In this study, building on recent experimental developments, we present laboratory observations of internal gravity wave turbulence in a linearly stratified fluid, performed in a large-scale, three-dimensional facility allowing the forcing of long-wavelength internal waves. Our setup allows to access large Reynolds numbers favoring the development of turbulent power-law spectra while keeping the Froude number relatively low in order to remain weakly non-linear. As the forcing amplitude increases, the flow seems to approach a wave turbulence regime: we indeed observe the progressive construction of a continuous distribution of energy both in the frequency and wave number spaces, whereas the spatio-temporal spectra indicate that the energy remains almost exclusively carried by internal gravity waves verifying the dispersion relation. We finally show that, as the transition to turbulence proceeds, the bicoherence spectrum of the velocity field becomes smooth over the internal wave frequency domain, taking values of the order of the Froude number. While these observations are in line with the phenomenology of weakly non-linear wave turbulence, the power laws in $k^{-3}$ we report over about a decade for the horizontal and vertical spatial energy spectra agree with the prediction that can be made from raw [...]

I. G. Aliyev, F. S. Latifov, A. M. Guliyeva

The structural element considered in the presented article consists, according to the geometric structure, of a coating and reinforcement elements, according to the mechanical characteristics of heterogeneous coatings along the length, having damage inside due to their physical structure and, finally, a system in contact with a viscoelastic medium. Taking into account one of the existing models (Winkler or Pasternak), the contact conditions between the coating and the reinforcement elements and the influence of the medium on the coating, the frequency equation of oscillation was solved, the results were analyzed. Theory of hereditary type damage under the action of external force is often used for taking into account the damages in the structure of a cylindrical shell forced to vibration. The Hamilton-Ostrogradsky variational principle is used for solving the problem. The results obtained can be used in the foundations of bridges built across mountain rivers. Such support is cost-effective. It should be noted that reinforcement and concrete mortar are also used in the internal parts of the cylindrical supports used. The article proposes to fill the inside of the cylindrical lid under study with clay.

Jozef Klembara, Marcello Ruta, Jason Anderson et al.

Abstract The Upper Carboniferous protorothyridid amniote Brouffia orientalis from Czech Republic is redescribed. Photogrammetric scanning of the holotype and only known specimen yields considerable new information on the skull and postcranium of this tetrapod and allows us to amend previous morphological descriptions to a substantial degree. A virtual 3D model built from photogrammetry scan data is used as the basis for a new reconstruction of the skull in dorsal, lateral, and ventral aspects and the lower jaw in lateral aspect. We expand and refine the diagnosis of Brouffia and compare it with other protorothyridids. We discuss the affinities of this taxon by coding it in a recently published data matrix of early amniotes, which we subject to maximum parsimony and Bayesian fossilized birth–death analyses. Brouffia emerges as the sister taxon to Coelostegus in all analyses, but the position of these two taxa within amniotes varies. In a parsimony analysis with unweighted characters, the (Brouffia + Coelostegus) clade forms the sister group to Synapsida. In various experiments of character reweighting, that clade is placed crownward of Captorhinidae on the stem-group of Reptilia, but anticrownward of remaining protorothyridids. The latter constitute either a paraphyletic array relative to Diapsida or their monophyletic sister group. The Bayesian analysis retrieves (Brouffia + Coelostegus) as the most basal plesion on the stem-group of Reptilia.

CONSTANZE WONDREJZ, EMAD NAGM, MARKUS WILMSEN

Systematic palaeontological and biometric-statistical analyses (classical clustering and linear discriminant analysis) of statistically significant populations of three early Turonian ammonite species from offshore marls of the Brießnitz Formation (Saxonian Cretaceous Basin, eastern Germany) were used to evaluate a formerly just visually suspected hypothesis of a size dimorphism within the taxa. The studied faunas can in fact be regarded as contemporaneous late early Turonian fossil assemblages derived from a palaeobiogeographic and depositional entity. However, only one of the three species passed the statistical tests. Neither in Lewesiceras peramplum nor in Mammites nodosoides can a dimorphism be proven. In both taxa, no other features than size can be recognised that differ significantly between the overlapping groups. Furthermore, adulthood cannot be proven due to the absence of unequivocal mature modifications. Thus, a combination of large intraspecific variability and commonly incompletely preserved (i.e., small) specimens dissembles dimorphic populations at a first glance. On the other hand, the suspected dimorphism in Spathites (Jeanrogericeras) reveliereanus was confirmed by the statistical analyses of numerous biometric parameters. Not only the maximum diameters but also the distinct apertural cross-sections and ornament show significant differences between the statistically clearly separated two groups. Furthermore, a decline in ornament and widening of the body chamber in fully grown macroconch specimens, regarded as a mature modification of the shell, demonstrate that the antidimorphs really differed in adult morphology. Thus, it can be shown that there are in fact two forms in the fossil assemblage of S. (J.) reveliereanus that, based on their morphological differences and lack of any overlap, represent micro- and macroconchs (inferred males and females) of an evidently dimorphic ammonite species. Finally, we conclude that simple visual inspection is commonly insufficient for the reliable proof of dimorphism in ammonoids.

Werner Schwarzhans

Abstract The coquina on the banks of the Oued Beth in the Rharb Basin in northwestern Morocco has long been known to be exceptionally rich in fossils. The stratigraphic position ranging from the Late Miocene to the Pliocene has been controversial, however. In the course of my master’s degree field work in 1975/76, I mapped the right bank of the Oued Beth from Dar bel Hamri to El Kansera. Following multiple recent studies in the general region, I here review my results and present an updated comprehensive stratigraphic and geologic frame for the first time. The coquina near Dar bel Hamri is interpreted to be of Early Pliocene age, possibly containing some reworking of Late Miocene fossils. The coquina and other locations along the Oued Beth have yielded a rich otolith assemblage, which is described in this article. It represents the first fossil otolith-based fish fauna described from Northwest Africa and contains 96 species, 16 of which are new. The new species in the order of their description are Diaphus maghrebensis n. sp., Ophidion tuseti n. sp., Centroberyx vonderhochti n. sp., Myripristis ouarredi n. sp., Deltentosteus planus n. sp., Caranx rharbensis n. sp., Trachurus insectus n. sp., Parapristipoma bethensis n. sp., Pomadasys zemmourensis n. sp., Cepola lombartei n. sp., Trachinus maroccanus n. sp., Trachinus wernlii n. sp., Uranoscopus hoedemakersi n. sp., Uranoscopus vanhinsberghi n. sp., Spondyliosoma tingitana n. sp., and Opsodentex mordax n. sp. In addition, a new species is described from the Tortonian and Zanclean of Italy: Rhynchoconger carnevalei n. sp. Some additional otoliths are described from another Northwest Moroccan location of Early Pliocene age near Asilah, 50 km south of the Strait of Gibraltar. The Early Pliocene fish fauna from Dar bel Hamri in the Rharb Basin is also of interest, because it constitutes the nearest Atlantic fauna of the time of the reconnection of the Mediterranean with the Atlantic and may have acted as a hosting area for the remigration of fishes into the Mediterranean. Indeed, the correlation is high between the Northwest Moroccan and the well-known time-equivalent Mediterranean fish fauna, but the Moroccan fauna also contains a good proportion of putative endemic taxa and taxa with tropical West African affinities that apparently did not migrate into the Mediterranean. Thus, the Early Pliocene fish fauna from the Rharb Basin represents a unique assemblage for which I propose the biogeographic term “Maghrebian bioprovince.” ZooBank LSID: urn:lsid:zoobank.org:pub:E01D698A-C1EE-4D32-B60D-4EF73AFFFCCF https://zoobank.org/65C520AE-72FB-4153-8D18-8695BB5A7E3F

Chathura Gamage, Vimukthini Pinto, Matthew Stephenson et al.

Performing tasks in a physical environment is a crucial yet challenging problem for AI systems operating in the real world. Physics simulation-based tasks are often employed to facilitate research that addresses this challenge. In this paper, first, we present a systematic approach for defining a physical scenario using a causal sequence of physical interactions between objects. Then, we propose a methodology for generating tasks in a physics-simulating environment using these defined scenarios as inputs. Our approach enables a better understanding of the granular mechanics required for solving physics-based tasks, thereby facilitating accurate evaluation of AI systems' physical reasoning capabilities. We demonstrate our proposed task generation methodology using the physics-based puzzle game Angry Birds and evaluate the generated tasks using a range of metrics, including physical stability, solvability using intended physical interactions, and accidental solvability using unintended solutions. We believe that the tasks generated using our proposed methodology can facilitate a nuanced evaluation of physical reasoning agents, thus paving the way for the development of agents for more sophisticated real-world applications.

Menachem Stern, Andrea J. Liu, Vijay Balasubramanian

Interacting many-body physical systems ranging from neural networks in the brain to folding proteins to self-modifying electrical circuits can learn to perform diverse tasks. This learning, both in nature and in engineered systems, can occur through evolutionary selection or through dynamical rules that drive active learning from experience. Here, we show that \added{learning in linear physical networks with weak input signals} leaves architectural imprints on the Hessian of a physical system. Compared to a generic organization of the system components, (a) the effective physical dimension of the response to inputs decreases, (b) the response of physical degrees of freedom to random perturbations (or system ``susceptibility'') increases, and (c) the low-eigenvalue eigenvectors of the Hessian align with the task. Overall, these effects embody the typical scenario for learning processes in physical systems in the weak input regime, suggesting ways of discovering whether a physical network may have been trained.

Giulio Rossolini, Alessandro Biondi, Giorgio Buttazzo

Deep neural networks exhibit excellent performance in computer vision tasks, but their vulnerability to real-world adversarial attacks, achieved through physical objects that can corrupt their predictions, raises serious security concerns for their application in safety-critical domains. Existing defense methods focus on single-frame analysis and are characterized by high computational costs that limit their applicability in multi-frame scenarios, where real-time decisions are crucial. To address this problem, this paper proposes an efficient attention-based defense mechanism that exploits adversarial channel-attention to quickly identify and track malicious objects in shallow network layers and mask their adversarial effects in a multi-frame setting. This work advances the state of the art by enhancing existing over-activation techniques for real-world adversarial attacks to make them usable in real-time applications. It also introduces an efficient multi-frame defense framework, validating its efficacy through extensive experiments aimed at evaluating both defense performance and computational cost.

Deep Ghosh, Sourav Gope, Satyanarayan Mukhopadhyay

The initial density of dark matter (DM) particles, otherwise secluded from the standard model (SM), may be generated at reheating, with an initial temperature ratio for internal thermalizations, $ξ_i=T_{\rm DM,i}/T_{\rm SM,i}$. This scenario necessarily implies inflaton-mediated scatterings between DM and SM after reheating, with a rate fixed by the relic abundance of DM and the reheat temperature. These scatterings can be important for an inflaton mass and reheat temperature as high as $\mathcal{O}(10^7 {~\rm GeV})$ and $\mathcal{O}(10^9{~\rm GeV})$, respectively, since the thermally averaged collision terms become approximately independent of the inflaton mass when the bath temperature is larger than the mass. The impact of these scatterings on DM cosmology is studied modeling the perturbative reheating physics by a gauge-invariant set of inflaton interactions upto dimension-5 with the SM gauge bosons, fermions and the Higgs fields. It is observed that an initially lower (higher) DM temperature will rapidly increase (decrease), even with very small couplings to the inflaton. There is a sharp lower bound on the DM mass below which the relic abundance cannot be satisfied due to faster back-scatterings depleting DM quanta to SM particles. For low DM masses, the CMB constraints become stronger due to the collisions for $ξ_i<1$, probing values as small as $\mathcal{O}(10^{-4})$, and weaker for $ξ_i>1$. The BBN constraints become stronger due to the collisions for lower DM masses, probing $ξ_i$ as small as $\mathcal{O}(0.1)$, and weaker for higher DM mass. Thus inflaton-mediated collisions with predictable rates, relevant even for high-scale inflation models, can significantly impact the cosmology of light DM.

Anne Hauzeur, Gilles Monin, Harold Lethrosne et al.

for axe head production in Bartonian (Eocene) silicite close to the mining complex of Jablines. They are attributed by the associated set of tools and the archaeological background to the later part of the Paris Basin Middle Neolithic (c. 4300–3700 BCE). The main characteristics of the knapping places are bifacial shaping to produce axe head preforms. Petrographical analyses show at first examination a close relation to the same silicite beds as those exploited at Jablines. Beside this, some of the artefacts indicate another way of raw material gathering which could match with the Bartonian silicite procurement on a larger scale. The workshop places may be distinguished as places of different function, mostly devoted to the first steps of preparation (roughing and shaping processes), but another to shaping stages, and a last one essentially concerned with the finishing of manufacturing rough-outs. Considering the very rare fragments of preforms collected on the site and the high quality of the rejected waste products, the skill level was high. From the first flaking of the block, contrary to what is usually inferred, indirect percussion was used since the first flaking of the block. These workshops add to the information from the other known similar places in this region of the Marne area, including the mining complex of Jablines itself. There were no settlements next to the mines, but in the surrounding areas, and the related distance remains to be explained.

Dagmara H. Werra

This monograph on the Neolithic flint workshops of the Bębło mining complex (Cracow district, Lesser Poland Voivodeship) appeared in 2021, published by the Archaeological Museum in Kraków with financial aid from the Ministry of Cultural and National Heritage, National Heritage Board of Poland and the Marshal’s Office of the Małopolska Region. The editor of the publication is Elżbieta Trela-Kieferling. The book appeared in the series „Biblioteka Muzeum Archeologicznego w Krakowie” [The Library of the Archaeological Museum in Kraków], edited by Dr hab. Jacek Górski. It is the tenth volume in the series, which has appeared since 2006, and is a commemorative volume, dedicated to the initiator of the series, Dr. Jacek Rydzewski.

Minghuan Zeng, Xiang Li, Yongjun Wang et al.

The impurity is inherently manifest in cuprate superconductors, as cation substitution or intercalation is necessary for the introduction of charge carriers, and its influence on the electronic state is at the heart of a great debate in physics. Here based on the microscopic octet scattering model, the influence of the impurity scattering on the electronic structure of cuprate superconductors is investigated in terms of the self-consistent T-matrix approach. The impurity scattering self-energy is evaluated firstly in the Fermi-arc-tip approximation of the quasiparticle excitations and scattering processes, and the obtained results show that the decisive role played by the impurity scattering self-energy in the particle-hole channel is the further renormalization of the quasiparticle band structure with a reduced quasiparticle lifetime, while the impurity scattering self-energy in the particle-particle channel induces a strong deviation from the d-wave behaviour of the superconducting gap, leading to the existence of a finite gap over the entire electron Fermi surface. Moreover, these impurity scattering self-energies are employed to study the exotic features of the line-shape in the quasiparticle excitation spectrum and the autocorrelation of the quasiparticle excitation spectra, and the obtained results are then compared with the corresponding experimental data. The theory therefore also indicates that the unconventional features of the electronic structure in cuprate superconductors is generated by both the strong electron correlation and impurity scattering.

Yang Li, Shifeng Xiong

Computer simulation models are widely used to study complex physical systems. A related fundamental topic is the inverse problem, also called calibration, which aims at learning about the values of parameters in the model based on observations. In most real applications, the parameters have specific physical meanings, and we call them physical parameters. To recognize the true underlying physical system, we need to effectively estimate such parameters. However, existing calibration methods cannot do this well due to the model identifiability problem. This paper proposes a semi-parametric model, called the discrepancy decomposition model, to describe the discrepancy between the physical system and the computer model. The proposed model possesses a clear interpretation, and more importantly, it is identifiable under mild conditions. Under this model, we present estimators of the physical parameters and the discrepancy, and then establish their asymptotic properties. Numerical examples show that the proposed method can better estimate the physical parameters than existing methods.

Angelina García, Yaín Garita-onandía, Dario A. Demarchi et al.

El presente trabajo tiene como objetivo contribuir al conocimiento de la historia poblacional de La Esperanza, Jujuy, en base al estudio de la diversidad y distribución relativa de linajes del ADN mitocondrial, sobre una muestra poblacional de 94 personas. Se analizaron las afinidades genéticas entre los linajes maternos encontrados en La Esperanza y 43 poblaciones sudamericanas a partir de datos tomados de la bibliografía. Los resultados muestran que los linajes nativos americanos constituyen el 100% de la muestra, siendo B2 el haplogrupo más frecuente (45%), seguido de D1, A2 y C1 con una contribución del 22%, 17% y 16%, respectivamente. Por último, un solo individuo presentó el linaje D4h3a. El análisis de distancias interpoblacionales revela bajos valores de distancia con las muestras Quechua de Huancavelica, Avá Guaraní y Pilagá. El análisis discriminante ubicó a la muestra de La Esperanza en el grupo Chaco, tanto cuando se la asignó a los grupos Chaco o Noroeste argentino, como cuando no se asignó previamente ningún grupo. En general, el análisis discriminante muestra un alto porcentaje de correcta clasificación de las poblaciones en los grupos en los que fueron asignadas inicialmente, lo que refleja la fuerte estructura geográfica de la variación genética. El análisis filogeográfico reveló vínculos genéticos con otras poblaciones del Noroeste argentino, particularmente de Jujuy y Salta y, en menor medida, con poblaciones del Gran Chaco. Los resultados obtenidos a partir de esta investigación reflejan la historia de una población surgida principalmente en torno al ingenio azucarero y a partir delaporte migratorio desde regiones vecinas de Argentina y países limítrofes, hecho que aseguró la disponibilidad de mano de obra a través del tiempo y condujo a la formación de una población con gran diversidad genética.

Atilio Nasti

Se sabe que los carroñeros pueden alterar significativamente una escena forense consumiendo, desarticulando y dispersando restos sobre la superficie del suelo. En este contexto, una rápida identificación de su presencia, es crucial para comprender las consecuencias sobre el registro forense. El propósito de este trabajo es evaluar el comportamiento de tres carroñeros: carancho (Caracara plancus), perro doméstico (Canis familiaris) y zorro pampeano (Lycalopex gymnocercus) en ambientes de humedales de la Provincia de Buenos Aires. Un cadáver de cerdo (Sus scrofa) de 25kg. depositado sobre la superficie del suelo se utilizó como emulación de un cadáver humano. Se registraron y evaluaron a lo largo de 37 días la acción de los carroñeros, observando su comportamiento, la secuencia de acceso a los restos, la desarticulación y la dispersión. Se identifican patrones direccionales de dispersión mayormente generados por el comportamiento de cada una de las diferentes especies. Se infiere una relación entre la secuencia de desarticulación y dispersión con el Intervalo Post Mortem.

Alexandru Maries, Chandralekha Singh

Drawing appropriate diagrams is a useful problem solving heuristic that can transform a problem into a representation that is easier to exploit for solving it. One major focus while helping introductory physics students learn effective problem solving is to help them understand that drawing diagrams can facilitate problem solution. We conducted an investigation in which two different interventions were implemented during recitation quizzes in a large enrollment algebra-based introductory physics course. Students were either (i) asked to solve problems in which the diagrams were drawn for them or (ii) explicitly told to draw a diagram. A comparison group was not given any instruction regarding diagrams. We developed rubrics to score the problem solving performance of students in different intervention groups and investigated ten problems. We found that students who were provided diagrams never performed better and actually performed worse than the other students on three problems, one involving standing sound waves in a tube (discussed elsewhere) and two problems in electricity which we focus on here. These two problems were the only problems in electricity that involved considerations of initial and final conditions, which may partly account for why students provided with diagrams performed significantly worse than students who were not provided with diagrams. In order to explore potential reasons for this finding, we conducted interviews with students and found that some students provided with diagrams may have spent less time on the conceptual analysis and planning stage of the problem solving process. In particular, those provided with the diagram were more likely to jump into the implementation stage of problem solving early without fully analyzing and understanding the problem, which can increase the likelihood of mistakes in solutions.